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In recent years with the advent of technological advancements, engine power & torque levels per unit engine displacement volume in motorcycles are showing significant increase. These powertrains however are prone to Torsional Vibration issues. The severity is even more with single cylinder engines. The Torsional Vibration Damper System (TVDS) in clutches has become critical as it plays an important role in isolating these torsional vibrations. Thereby increasing the lifespan of the critical powertrain components. The major challenge with TVDS is, it must transmit the high torques on one hand and effectively keep the high pulsations in torque away from the rest of drive train on the other. These are conflicting requirements & often result in a design compromise. Further this is revealed only at full vehicle testing. Thus it requires the full vehicle functional prototypes to be ready for first level evaluation of TVDS.

Safety aspect has been a key requirement in designing braking system. However, non-safety aspect like NVH and thermal performance are gaining equal importance. High engine capacity (cc) motorcycles are prone to thermal and NVH issues as braking energies are more. Therefore, virtual validation of brake disc system by considering both dynamic and thermal load with predefined assumptions is a toughest challenge when confronted with reality boundary conditions. Thus, the paper comes in a unique way of coupling dynamic and thermal load executed between multi body dynamics (MBD) and heat transfer equation which will convey results closer to real time scenario. MBD solves motion and the dynamic influence on heat transfer is calculated using “sliding boundary condition”. A series of repeated braking condition are performed on front brake disc of motorcycle. The results obtained from the analysis shows critical temperature rise.

With advancements in powertrain technologies & light weighting of vehicle structures, the average driving speeds of motorcycles are increasing. This makes it important to safeguard the vehicle structure from possible impact loads or crash events. The front suspension of a motorcycle typically consists of telescopic front fork which acts as a structural member as well. Thus modern vehicle front forks should be designed keeping in mind frontal impacts as well. Which means the structural stiffness of front fork needs to be optimally designed so that during impacts, the structure should deflect absorbing the bulk of the impact energy safeguarding the rest of the vehicle structure including chassis. At the same time the front fork should not break. The popular design improvement techniques like increasing section modulus, heat treatments to increase strength may or may not have positive effect on impact strength.

Vehicle suspension systems are designed keeping in mind the requirement for vehicle articulations and load transfer between chassis & tires. Another factor which is given due importance is the avoidance of extremities with end cushions. As such extremities result in generation of impact loads which could eventually lead to failure of end cushions and the vehicle chassis. Number of occurrences of these extremities is an indication of how good a vehicle suspension design is. This paper presents a methodology developed that converts a shock absorber to a potential sensor, that not only measures the travel and velocity, but also the different kind of loads generated at different events. It includes instrumentation, data acquisition and its analysis for evaluating the performance of the shock absorber and also to provide additional insights into its design.

Ride comfort and handling present conflicting requirements on damping properties of a suspension system. While ride comfort demands a softer damping, a higher damping force makes the ride handling better. Conventional dampers, being solely velocity dependent, are always a compromise between these two requirements. A damper can be made position sensitive, in addition to its velocity dependence, in order to obtain the best of both the worlds. A position-sensitive damper can have a softer damping force for low amplitude road excitations, as observed on highways and a higher damping force for higher amplitude road excitations, as observed in off-road conditions. Thus such a damper can be optimized not only for a good comfort, but for a good handling performance also. General designs for a position sensitive damper involve a bypass arrangement around the piston. This paper discusses an alternate arrangement for achieving position sensitive damping and its benefits.